Dragon not eating

My dragon is 2 yr old male. I bought him from a local pet store for Christmas and honestly I have no idea how he is even still alive. And the pet store is no help at all.
Here my problems... He will not eat... Like at all. I bought large crickets and he wouldn't touch them... OK so I bought 10 tiny crickets... Yeah they chrip now and still all there. I'm gonna have to murder these crickets as well.

I've tried variety of greens,squashs, applesauce, carrots,green beans, and other veggies. Nothing. He completely ignores his food dish. I've tried every worm I can think of. Nope. I even tried the breaded dragon PetSmart soft pellets. Nope All he does is sit on his rock. He has a 100 gal tank and he never leaves his rock. I have never seen him go by his water dish. So like I said idk how he is alive because he doesn't eat, far as I know he doesn't use the water dish... And he never poops. He gets a bath every 3 days cuz I was told that help him go... But he has only pooped once this whole month of March. And that was like March 3rd.

His tank is a 100 gal. Reptile carpet through out. Two gauges on both sides of the tank to measure temps. I have zoo med equipment. I've never had a problem with his tank keeping heat. His lights all work and he gets his uv. So I'm just stumped on how to take care of him. Someone please tell me what to do

He looks quite healthy, maybe a bit dehydrated but not bad. He could be wanting to burmate. Are you by chance using any type of light emitting heat source at night? Also, what type of uvb are you using..coil or long tube? How long are the lights on(length of his day)?
There are several things that can cause this.

I got what the guy at the pet store gave me. The red bulb is heat at night. The big white bulb is supposed to be uv daylight. He also has a large heating Matt under his tank and a small heating Matt on the side of his tank

Greetings,
As Gormagon began mentioning, dragons cannot sleep properly if there is light in their enclosure while they are trying to sleep - this includes that red night light. I would highly recommend removing it, or at least not using it. If your household temps/enclosure temps get below 65 degrees at night, you could use a CHE, ceramic heat emitter, that produces heat with no light.

You mention the white basking light is the UV light, can you confirm if it's a MVB? (Mercury vapor bulb)
A MVB naturally produces a bright white light, heat, and UV waves. If this is a normal basking bulb he will not be getting any UV from this. Some bulb brands are also better than others, so knowing the make of the bulb might help us as well.

You also mention having gauges in the enclosure to read temp. Are they the stick on dials? If so, please note these are known to be horribly inaccurate. Mine was off by 20 degrees and I did not realize until I purchased a laser temp gun from amazon.

As Gormagon said, he looks healthy still! Lack of appetite is unfortunately a common side effect of several possible issues, or even no issue at all (shed, brumation, mood, etc.)
Knowing the exact temp he's basking at would be a great start, and confirmation on the UV light as well.
If you could, could you provide photos of his luxurious 100g enclosure?
That may help to make some adjustments beyond what has already been provided to help boost his appetite back up

Thanks I will post more picks and find out about the bulb as soon as I'm out of work.